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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
for the guidance of teachers
0654 CO-ORDINATED SCIENCES
0654/51
Paper 5 (Practical), maximum raw mark 45
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of
the examination. It shows the basis on which Examiners were instructed to award marks. It does not
indicate the details of the discussions that took place at an Examiners’ meeting before marking began,
which would have considered the acceptability of alternative answers.
Mark schemes must be read in conjunction with the question papers and the report on the
examination.
• Cambridge will not enter into discussions or correspondence in connection with these mark schemes.
Cambridge is publishing the mark schemes for the May/June 2011 question papers for most IGCSE,
GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level
syllabuses.
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MARK SCHEME for the May/June 2011 question paper
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er
International General Certificate of Secondary Education
Page 2
1
Mark Scheme: Teachers’ version
IGCSE – May/June 2011
Syllabus
0654
Paper
51
(a) 2 readings for inhaled air ;
[1]
(b) 2 readings for exhaled air and average of 2 readings less than average of
2 readings in (a) ;
[1]
(c) (i) average for inhaled air ;
average for exhaled air ;
inhaled air = higher reading than exhaled air ;
[3]
(ii) time for atmospheric / inhaled air longer ;
more oxygen ;
(accept reverse argument for 2 marks) (ignore references to carbon dioxide)
[2]
(iii) exhaled – cloudy and atmospheric / inhaled – clear ;
CO2 linked to cloudiness or to B ;
respiration / breathe out CO2 / no CO2 in A ;
[3]
(d) (variable) – different exercise levels ;
(control) – same person / same food / same temperature ;
(reliability) – repeats ;
(measurements) – breaths per minute ;
(equipment) – stopwatch / other equipment related to measurement of breathing
rate ;
measurement of breathing rate ;
[max 5]
[Total: 15]
2
(a) measurement clearly in mm ;
[1]
(b) table
5 sets of results ;
force correct (2.0, 3.0, 4.0, 5.0) ;
increase in length greater as goes down ;
increase in length is correct ;
[4]
(c) graph
axes labelled correctly ;
suitable scale ;
plotting correct for at least 4 points ;
[3]
(d) yes, with suitable explanation ;
[1]
(e) suitable straight line or curve drawn related to answer in (d) ;
[1]
(f) read correctly ;
[1]
© University of Cambridge International Examinations 2011
Page 3
Mark Scheme: Teachers’ version
IGCSE – May/June 2011
Syllabus
0654
Paper
51
(g) proportional (if straight line is drawn) / not proportional (if a curve is drawn) ;
[1]
(h) measure length after removing weights ;
[2]
(i)
;
[1]
(accept if elastic limit shown on graph)
[Total: 15]
3
(a) violet / lilac / purple ;
[1]
(b) litmus goes red / litmus bleached (ignore litmus goes blue) ;
steam / water vapour / smoke / goes brown / goes yellow ;
[2]
(c) (i) dissolves in cold water ;
solution pale brown / orange / yellow ;
[2]
(ii) brown ppt. / orange ppt ;
litmus red to blue ;
[2]
(iii) red brown ppt. / orange ppt ;
[1]
(d) test for chloride ion
added silver nitrate ;
no ppt. ;
test for sulfate ion
added barium chloride ;
white ppt. ;
(e) (any order)
iron(III) / Fe3+ / Fe (III) and valid reason ;
sulfate / SO42- and valid reason ;
ammonium / NH4+ and valid reason ;
[4]
[3]
[Total: 15]
© University of Cambridge International Examinations 2011